Technical Abstract:
Knowledge of soil carbon (C) and moisture contents is vital for crop and soil management. Current techniques for measuring these components require independent techniques that could be labor intensive and time consuming. The prospect of simultaneously measuring the soil C and moisture content in real - time using the INS system has been explored in this study. The system utilizes a 14 MeV neutron generator (NG) operated in the pulsed mode, whereby C, H and O in the soil is determined by measuring their characteristic gamma - ray emission following their interaction with neutrons. Laboratory experiments were conducted at the Soil Analysis Facility at Brookhaven National Laboratory, and field experiments were carried out at the Pee Dee Clemson University Research Station in Florence, South Carolina. In the field experiment, C, H and O were measured by the INS instrument at ten sites that represented different landscape positions ranging from the foot slope to upslope and across different soil types. At each site, volumetric soil moisture content was measured using the theta probe and gravimetric moisture content measured on samples collected to 30 cm depth. We present preliminary data on the relationship between the H and O signals and soil moisture content.